Refrigerating apparatus



July 21, 1936. A. PHILIPP REFRIGERATING APPARATUS' 2 Sheets-Sheet 1 Original Filed May 10, 1952 INVENTOR. Law/emu 4 P/l/L/PP L. A. PHILIPP REFRIGERATING APPARATUS July 21, 1936.

2 Sheets-Sheet 2 Original Filed May 10, 1932 BY I W a. 0M

' ATTORNEY.

Patented July 21, 1936 UNITED STATES PATENT OFFICE a mum I s Lawrence A. Phiiinr, Detroit, ma, allignor to Kclvinator Corporation, Detroit, Mich, a corporaflon of mo 1 Claim. (c1. est-41) This invention relates to refrigerating apparatus, and more particularly to an apparatus for and a method of maintaining a number of different refrigerating compartments at 'diflerent temperatures.

This application is a division of my co-pending application Serial No."610,472 flied May th, 1932, for Refrigerating apparatus.

Heretofore, it has been the practice to maintain a temperature differential between a number of different refrigerant evaporators by means of pressure responsive valves associated with some or all of the refrigerant evaporators. These valves prevented the withdrawal of refrigerant vapor and heat from the different evaporators until a predetermined pressure existed therein. Usually, these evaporators are joined to a common refrigerant vapor conduit connected to an intermittently operated compressing unit, the operation of which was controlled by changes in pressures in the vapor conduit. Valves of this type have been found to be undesirable in that they are very likely to become out of proper adjustment or misadjusted by someone unfamiliar with the operation of the system. This causes abnormal operation of the system. In addition, the valves are usually complicated and expensive to manufacture. Also, in systems of this type, refrigerant vapor was frequently drawn into the compressor at the low pressure existing in the evaporator operating at a lower temperature than the others in response to a demand for refrigeration by that evaporator. This low pressure vapor was then compressed to its condensing pressure. Under these conditions, the compressor was required to do more work than it would if the refrigerant to be compressed was at a higher pressure.

One of theobjects of my invention is to provide an improved and simplified arrangement for maintaining a number of different compartments at a-number of different temperatures by means of a multiple suction pressure compressor.

Another object of my invention consists in providing a compressor with a plurality of fluid suction ports wherebythe fluid to be compressed is drawn into the compressor at different times during the suction stroke of the compressor.

'Another object of my invention consists in the provision and adaption of a rotary compressor for operation at a plurality of suction pressures and the simultaneous compression of the fluid re-. ceived at diiferent suction pressures.

Further objects and advantages of the presentinvention will be apparent from the following. description, reference being hadto the accompanying drawings, wherein a preferred form of the present invention'is clearly shown.

Inthe drawings: 6 Fig. 1 is a diagrammatic representation of a refrigerating system embodying .features of my invention;

Fig. 2 is a diagrammatic representation of a modified form of refrigerating system embodying 10 features of my invention;

Fig. 3 is a side view in cross section of a motorcompressor unit embodying features of my invention:

Fig. 4 is a view taken along the line 4-4 of Fig. 3; and

Figs. 5 to 8, inclusive, show diagrammatically difierent positions of the compressor piston during operation thereof.

Referring to the drawings, and particularly Fig. 1, the numeral 20 designates, in general, a refrigerating system diagrammatically representing as including a condensing element 22 and refrigerant evaporators 24 and 26, which may be of the flooded float control type, although other 25 types may be used. Evaporators 24 and 2B are adapted to refrigerate compartments 28 and 30, respectively, at different temperatures by means of agmultiple suction compressor 3| (see Fig. 4) forming a part of the condensing element 22, which is hereinafter described in detail.

Liquid refrigerant is supplied to the evaporators 24 and 26 by means of a common liquid supply conduit 32 and evaporated refrigerant is withdrawn from the evaporators 24 and 26 through vapor conduits 34 and 38 at different suction pressures by means of the multiple suction compressor 3|, the conduit 34 being connected to 'a relatively high suction pressure port 42, and the conduit 36 being connected to a lower suction pressure port 44 of compressor 3|. The compressor 3| compresses the refrigerant vapor and delivers it to a condenser 43 wherein it is liquefled and from which it is delivered to a liquid refrigerant receiver 45 to which the conduit 32 is connected. 7

Under the above conditions, the temperature of evaporator 24 and the temperature in compartment 28 will be maintained lower than the temperature of evaporator 26 and the temperature in the compartment 30, although the evaporators 24 and 26 may be of the same capacity and the insulation surrounding the compartments be the same. This is due to the difference in suction pressures of the compressor 3| and the 55 member 84. ranged for movement within the walls of the difference in removal of heat from evaporators 24 and 26 caused thereby. Consequently, it will be noted that I have arranged for maintaining a temperature differential between a number of different refrigerant evaporators by means of a multiple suction compressor.

As shown in Figs. 3 and 4, the compressor 3| is enclosed in' a hermetically sealed casing 58. The

casing 50 is formed preferably of three parts;

namely, a central casting member 54 and sheet metal enclosures 55 and 56 joined to the casting 54 at opposite: ends thereof. An electric motor .68 is also enclosed within the casing 50. The motor includes stator 62 and rotor 64. Rotor 84 is carried by shaft 66. which shaft is journaled in a bearing 68, preferably formed integrally with the casting member 54. On the opposite end of "the shaft 66, I have mounted the compressor 3 I. This compressor is of the so-called rotary type and includes a cylinder blockfll clamped between a vertically extending wall member I2 formedppref- I erably integral with the-casting member. 54, and

an outer plate member I4 by means of screws I5. Within the cylinder block I0 there is provided a piston chamber 11 in'which there is disposed a' piston member I8 arranged for movement about the cylindrical wall of the chamber 11 by means of an eccentric member. 88 carried by shaft 66 and locked thereto by means of key 8 I. The shaft 66 extends through the chamber 11 and the shaft end I9 is Journaled in a bearing 82 carried by plate I4. The piston is provided with a blade 83, which extends through an opening 86 in an oscillating The oscillating member 84 is arcylinder block III, while the blade 83 is arranged for reciprocation within the opening 86 provided in the member 84. By this arrangement, rotation suctionpressure port 42 at an angle considerably less than 180 therefrom. However, it is to be understood that the port 42 may be disposed at any place about the periphery of the chamber 11,

depending upon the capacity of the compressor desired. A discharge port 92 is provided for the discharged gas compressed within the chamber II. A suitable. discharge valve is provided in the discharge port 92. 'As shown, the high compressed gas is discharged within the sealed casing 50 whence it passes through the outlet 86 provided in casing 50, through conduit 81 to the con-- denser 43'.

As shown in Fig. 4, the piston member I8 is compressing gas on, the righthand side thereof and gas is being drawn into the chamber II on the left hand side thereof. In order to more clear- 1y describe the operation of the compressor, I have shown in Figs.- 5 to 8; inclusive, various positions assumed by the piston within the chamber 1'! a is just starting on its suction stroke whereby reduring operation thereof. In Fig. 5, the piston I8 frigerant vapor is being drawninto the chamber 11 through the port 44 and the piston I8 is compressing gas in the chamber .11 between its right hand side and the wall of'the chamber II. Fig.6 shows the piston after it has moved past the high suction pressure port 42 whereby refrigerant vapor is being. drawn into the chamber 'I'I through fore it is compressed by the compressor.

.the port 42, and in so doing, this refrigerant va por, which is at a higher pressure than the vapor which enters the chamber 'II through port 44,

vents the further flow of vapor into chamber 'I'I through port 44 at this time. Thus, the high pressure vapor compresses the low pressure vapor quired of the compressor than if it were required to compress gas at a pressure which is equal to that which enters into the chamber 11 through port 44. As will be noted in the drawings, the suction stroke of the piston I8 from port 42 to the discharge port is greater than the distance between the ports 44 and 42. Thus, by the present arrangement of the high and low pressure suction ports, more refrigerantwill be'drawn into the chamber I! through port.42 than through port 44. In order to prevent back flow of gas into the conduits 34 and 36, I have provided these conduits with check valves I06 and IDI, respectively. Fig. 7 shows the piston memberin the down stroke just after the refrigeranthas been discharged through the discharge valve 94. Fig. 8 shows the piston about to start on its suction stroke. A

Preferably, the system is intermittently operated in response'to changes in pressures within the conduit 34; The evaporators! and 26 are of- .the flooded type, in which the pressure of the refrigerant bears a directrelation to the temperature of the'evaporators. Consequently, the operation of the system will be controlled in response to changes in temperature within the evaporator 24. In a system of this type, it is immaterial, however, whether the operation of the compressor is,

including a plurality of refrigerant evaporators and that I have provided for maintaining a temperature differential between the evaporators whereby a number of different compartments are cooled at different, temperatures by means of a 'multiple suction compressor, and that I have further taken. advantage of such an arrangement by precompressin'g some of the vapor be- This arrangement is particularly advantageous in that the compressor is required to do less work and the capacity thereof is greater than if'it were required to compress gas from a pressure equivalent to that existing in a lower temperature evaporatorto a pressure at which the refrigerant Thus, itwill be noted that I have provided a simplified form of maintaining would condense;

any of the so-called household" refrigerators.

The system includes a condensing element I20 and refrigerant evaporators I22 and I24. .Evaporator I22 is adapted to cool compartment I26,

which compartment may be a food storage com- 5 partment of a household refrigerator.

Preferably, this compartment is to be maintained at temperatures suitable for refrigerating food articles stored therein. Evaporator I24 is adapted to cool an insulated compartment I30 at temperatures lower than that to which evaporator I22 cools compartment I26. Evaporator I24 is used primarily for freezing ice cubes, and for this purpose I have provided an ice tray I32, which is adapted to rest on a lower portion I34 of evaporator I24. v The compartment I30 may be called a freezing compartment and may be located in the same household refrigerator cabinet as the compartment I23 is located. Liquid refrigerant is supplied to the evaporators I22 and I24 by means of liquid supply conduits I40 and I 42, which are connected to a liquid refrigerant header I 44 The evaporator-I24 may be of the flooded float control type wherein a constant level of liquid refrigerant is maintained by means of a float valve mechanism (not shown). Liquid refrigerant is supplied to the header I44 through a conduit I50 under the control of a high side float I52. Evaporated refrigerant is withdrawn from the evaporator I22 through the top of the header I44 by means of the conduit 34, which is'connected to thehigh suction pressure port 42 of compressor 3|. Evaporated refrigerant is withdrawn from the evaporator I24 by means of the conduit 36 which is connected to the relatively low suction pressure port 44 of the compressor 3|. Any suitable means may be provided for controlling the operation of the motor-compressor unit and, as shown herein, I have provided a pressure responsive switch I58 responsive to changes in pressure within the conduit 34 for actuating switch I56 to cut the motor in and out of circuit with the power mains I45 in response to changes in pressures in conduit 34. By the present arrangement, the evaporator 45 I22 will be subjected to considerably more heat than the evaporator I24, and, consequently it will be necessary to remove this heat in order to maintain predetermined temperatures within the compartment I26. This heat is due to the fact that in household refrigerators the door this reason, I have arranged for withdrawing the evaporated refrigerant from the evaporator I22 by means. of the high suction pressure portion 01' the compressor and have arranged for withdrawing the evaporated refrigerant from the low temperature evaporator I24 by utilizing the lower suction pressure part of thecompressor.

The evaporator I24 may be of a larger heat capacity than the evaporator I22 and. asshown,

the evaporator I24 is utilized primarily for freezing ice cubes. Thus, the possibility of heat transfer into this compartment is considerably less than the heat transfer into compartment I26.

For this reason, it is desirable to connect the evaporator I22 to the high suction pressure port 5 of the compressor. In the system shown in Fig. 2, the high temperature evaporator is shown connected to the high suction pressure port of the compressor 3|, while in Fig. 1 the lowv temperature evaporator is shown connected to the high 10 suction pressure port of the compressor. How- 4 ever, this arrangement may be changed to suit the conditions of the refrigerating system. In the system shown in Fig. 1, the evaporators are of .the same heat capacity, while in Fig. 2, the 15 evaporators shown are of different heat capacities and are arranged for cooling different sized compartments'in which the heat removal probtherein without departing from the spirit of the 30 invention or from the scope of the appended claim.

What I claim as my invention is:

, A rotary fluid pump for creating different backpressures comprising, in combination, means pro- 35 viding a substantially cylindrical chamber for fluid to be compressed and being provided with an inlet port connected, with a sourceof fluid to be subjected to a predetermined back pressure, I

an outlet port, a second inlet port located inter- 40 mediate said inlet and outlet ports and connected with asecond source of fluid to be subjected to a different back pressure, said means including a supporting plate providing said inlet ports, a substantially cylindrical piston within 45 said chamber, said piston being of smaller diameter than said chamber, a shaft journalled in said supporting plate and extending into said 'chamber, eccentric means on said shaft associated with said piston for operating said piston 50 inone direction only and for urging said piston toward the wall of said chamber and about said chamber wall, said second inlet port being so positioned that a movement of said piston past said second inlet port will establish open com- 55 munication in said chamber between said first and second inlet ports, and a movement past said outlet will establish open communication in said chamber between said second inlet port and said outlet port, and independent check 30 valves associated with each inlet port and operable by the diiferences in pressures created in the apparatus for preventing back flow of fluid through said inlet ports.

LAWRENCE A. PHILIPP. 

